Answer:
4.42 x 10⁷ W/m²
Explanation:
A = energy absorbed = 500 J
η = efficiency = 0.90
E = Total energy
Total energy is given as
E = A/η
E = 500/0.90
E = 555.55 J
t = time = 4.00 s
Power of the beam is given as
P = E /t
P = 555.55/4.00
P = 138.88 Watt
d = diameter of the circular spot = 2.00 mm = 2 x 10⁻³ m
Area of the circular spot is given as
A = (0.25) πd²
A = (0.25) (3.14) (2 x 10⁻³)²
A = 3.14 x 10⁻⁶ m²
Intensity of the beam is given as
I = P /A
I = 138.88 / (3.14 x 10⁻⁶)
I = 4.42 x 10⁷ W/m²
Let say for every 5 s of time interval the speed will remain constant
so it is given as
v(mi/h) 16 21 23 26 33 30 28
now we have to convert the speed into ft/s as it is given that 1 mi/h = 5280/3600 ft/s
so here we will have
v(ft/s) 23.5 30.8 33.73 38.13 48.4 44 41.1
now for each interval of 5 s we will have to find the distance cover for above interval of time
so here it will cover 1298.1 ft distance in 30 s interval of time
This because your face has more sensitive tissue than anywhere else in your body
Hope this helps
The answer is B friction force
Answer:
Explanation:
Let's answer these statements
.1) True. This is the law of reflection.
.2) False. The speed of light depends on the index of refraction n = c / v
v = c / n
.3) True. The frequency creates a forced oscillation, whereby the atoms re-emit at the same incident frequency
.4) False. The index of refraction is a measure of the ratio of the speed of light in a vacuum and the material environment, the ability to change the trajectory is given by the law of refraction
.5) True. True due to the change in beam trajectory due to the law of refraction
.6 False. The phenomenon occurs when you pass from a medium with a higher index to one with a lower ratio, because the refracted beam separates from the normal
.7) True.
.8) False so that the lightning approach is valid Lam >> d,
.9) True.
